Method and apparatus for coating workpieces

Abstract

A method and arrangement for the vacuum coating of workpieces by arc evaporation, comprises at least one evaporating cathode with a surface to be evaporated, an axis of the cathode intersecting the cathode surface. Workpieces to be coated are arranged around the axis at locations which are spaced radially outwardly and at an axial distance from the cathode surface. In order to prevent direct line of sight communication between the cathode surface and the workpieces, a visual shield is positioned between the cathode surface and the workpieces, which at least partly surrounds the axis. In this way, the ions which are evaporated from the cathode surface are deflected outwardly around the visual shield and toward the workpieces.

We claim: 
     
       1. A method for coating workpieces by arc evaporation, comprising the steps of: evaporating ions from a cathode surface having an axis intersecting said surface;   arranging workpieces to be coated around said axis at locations radially outward and axially distant from said cathode surface;   providing visual shield means between said cathode surface and said workpieces at least partially surrounding said axis to prevent said workpieces from line of sight communication with said cathode surface; and   deflecting said ions radially outwardly around said visual shield means towards said workpieces.   
     
     
       2. Vacuum coating arrangement for coating workpieces, comprising an evaporation chamber containing therein: at least one evaporation cathode with a surface to be evaporated;   at least one anode;   with respect to an axis intersecting said cathode surface, axially and radially distant from said surface, an annular area surrounding said axis for accommodating workpieces;   between said cathode surface and said annular area a visual shield substantially surrounding said axis and preventing workpieces within said area from line of sight contact with said surface; and   deflection means to deflect ions evaporated from said surface, radially outwardly around said visual shield into said annular area.   
     
     
       3. The arrangement of claim 2, comprising a second evaporation cathode, a second visual shield and second deflection means, said second cathode, shield and deflection means being substantially symmetrically arranged with respect to said first cathode, visual shield and deflection means and with respect to a plane through said annular area and perpendicular to said axis. area. 
     
     
       4. The arrangement of claim 2 said at least one cathode being associated with an annular anode axially distant therefrom, said deflecting means leading said ions through the opening of said annular anode. 
     
     
       5. The arrangement of claim 2 comprising a tube-like member arranged substantially coaxial to said cathode surface, said member being electrically energizable at an anodic potential with respect to said cathode. 
     
     
       6. The arrangement of claim 5, the end of said tube-like member remote from said surface acting as a said visual shield between said annular area and said cathode surface. 
     
     
       7. The arrangement of claim 5, said tube-like member being provided at its end remote from said cathode surface, with a radially projecting outward collar. 
     
     
       8. The arrangement of claim 5, comprising adjacent the end of said tube-like member remote from said cathode, the inner diameter of said annular anode being larger than the diameter of said tube-like member. 
     
     
       9. The arrangement of claim 2, comprising at least two annular anodes axially distant from said cathode, said anodes being energizable at an anodic potential with respect to said cathode. 
     
     
       10. The arrangement of claim 9, said anodes being energizable at different anodic potentials. 
     
     
       11. The arrangement of claim 2, comprising a magnetic arrangement generating a magnetic field substantially directed from said cathode surface into said annular area and around said visual shield. 
     
     
       12. The arrangement of claim 2, comprising at least one thermionic cathode adjacent said evaporation cathode for providing a low voltage arc discharge. 
     
     
       13. The arrangement of claim 12, said thermionic cathode being arranged within a cathode chamber, said cathode chamber being separated from said evaporation chamber by a separating wall, said thermionic cathode being linked with said evaporation chamber through an opening within said separating wall. 
     
     
       14. The arrangement of claim 13, wherein said wall comprises one of said at least one evaporation cathode. 
     
     
       15. The arrangement of claim 2 being rotational symmetrical with respect to said axis. 
     
     
       16. The arrangement of claim 2, further comprising an anode disposed radially outward from said annular area. 
     
     
       17. The arrangement according to claim 2, comprising a magnetic arrangement generating a first magnetic field directed from said cathode into said annular area and a second magnetic field symmetrical with respect to said first magnetic field and with respect to a perpendicular plane on said axis and through said annular area. 
     
     
       18. The arrangement according to claim 2, said deflection means comprising a magnetic arrangement generating a magnetic field, at least a part thereof leading from said cathode surface into said annular area, said magnetic arrangement being modulatable to generate a magnetic field which is controllably variable in time. 
     
     
       19. The arrangement of claim 18, two parts of said magnetic field being generated by independently modulatable magnetic arrangements. 
     
     
       20. The arrangement of claim 2, said deflection means comprising at least one magnetic coil. 
     
     
       21. The arrangement of claim 20, said at least one magnetic coil being arranged coaxially to said axis.